centre and corners reasonably sharp wide open and by f/2 it is matching the Olympus m.ZD 75mm f/1.8 lens - as centre becomes much sharper at f/2 and extremely sharp at f/2.8-4, corners sharpest at f/4

some longitudinal CA but flare, ghosting, distortion, lateral CA, spherical aberration, coma and astigmatism are well controlled - should be a very nice lens for wide field astrophotography to give nice star images across the frame

fairly severe vignetting wide open which is also evidenced by the oval shaped out-of-focus highlights in the corners but this resolves as lens is stopped down to f/2.5.

Wide open, the Panasonic Leica has notably higher contrast straight out of camera. It really has remarkable contrast for an f/1.2 lens.

The Fuji exhibits some spherical aberration wide open, which may show as a glow with high contrast subjects such as white text on a black background. The Panasonic Leica exhibits extremely minimal spherical aberration.